The gameplay of this is fun! I found myself wishing it was longer but this works perfectly well for a game jam.
My critiques are just things others have already mentioned (namely the UI; health bar not appearing unless in shop, coin count being unreadable in shop due to being on top of the white arrow, some item descriptions are too long so the text becomes really small) A win/loss screen would be nice too, I played through twice to see if I had won against the boss or if I died since it's not very clear. Also a clearer indicator that you've taken damage (maybe a hurt sound?) unless this is fixed when you can see the health bar haha.
The boss also seems like it's a sharp increase in difficulty compared to the normal enemies you encounter, but maybe that was just me not having very many encounters prior to the boss.
I really like the selection of bullets and the randomness in the order you receive them, though since you're shooting them all as fast as possible while dodging, the order doesn't seem to matter much. (As opposed to something like Peglin.) I can't really comment on bullet synergy since it's too short to get a good feel for it, if you're trying to make players curate their "builds." The wind bullet is particularly interesting to me though since it also pushes the player back, so it feels like your choice of bullets has more effect on you and the environment. It might be fun to have more of those trade-offs, like the flame bullet being really good at killing a bunch of enemies at once but it also burns you if you jump in the trail.